## CassiusDelaney 3 years ago one sec ill post a pic of the thingy :)

1. CassiusDelaney

here it is :)

2. rctnk99

The dartboard or the discounts?

3. CassiusDelaney

Dart board that ones next ;)

4. rctnk99

Ok, a probability question. You have 4 darts and 3 possible values. It's a combination since the order of the darts doesn't matter.

5. CassiusDelaney

so the values are 1,5,9 5,9,1 and 9,1,5?

6. rctnk99

Ah, sorry, it's a permutation.

7. CassiusDelaney

oh ok

8. rctnk99

The formula for a permutation is n! over (n-r)!

9. rctnk99

n is 4, r is 3

10. CassiusDelaney

so 1

11. rctnk99

Do you know factorial notation?

12. CassiusDelaney

nope :/

13. rctnk99

Factorial is multiplying a number, then multiplying by one less, and it continues down to 1. So 4! is 4*3*2*1, and 1! is 1. 4*3*2*1 also happens to be your answer.

14. CassiusDelaney

what does the * mean?

15. rctnk99

Multiply

16. CassiusDelaney

so 24?

17. rctnk99

That's it.

18. CassiusDelaney

thanks buddy :)

19. rctnk99

While it's open, might as well solve the other one too.

20. CassiusDelaney

oh yeah thanks :)

21. rctnk99

Imagine you start at 100 dollars. What's 10 percent off of that?

22. CassiusDelaney

10...

23. rctnk99

So 100-10 is 90. What is 20 percent of 90?

24. CassiusDelaney

18?

25. rctnk99

Yep. 90-18 is 72. So 100-72 is your total discount.

26. rctnk99

Or 28%, to be exact.

27. CassiusDelaney

oh ok thanks